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Re: [Discuss-gnuradio] Question regarding the DBSRX frequency range and
Eric A. Cottrell
Re: [Discuss-gnuradio] Question regarding the DBSRX frequency range and bandwidth
Wed, 27 Jun 2007 21:49:01 -0400
Thunderbird 184.108.40.206 (X11/20060911)
Matt Ettus wrote:
> When Maxim states that their maximum LPF bandwidth is 33 MHz, they
> mean one-sided bandwidth (i.e. 0 to 33 MHz). Since it is used in a
> direct conversion IQ system, that actually gives a 66 MHz bandwidth (-33
> MHz to +33 MHz). Since that is beyond nyquist for our ADC, I spec to 60
> MHz (+/- 30 MHz).
> On the low end, they specify 4 MHz, which is really 8 MHz (+/-4 MHz)
> of RF bandwidth. The filter is actually capable of going to a much
> narrow frequency, but it is outside of Maxim's specs, since nobody in
> the small satellite dish market cares about less than 8 MHz of BW. So I
> spec that it goes down to 1 MHz wide. It should be noted that when you
> go below 4 MHz wide (2 MHz in Maxim-speak) that your noise floor will
> rise a bit and phase noise may also rise.
I assume the parameter for the setbw function is the double-sided
bandwidth and not Maxim-speak?